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By J. P. Connell

The U.S. Bureau of Mines awarded a contract to Morrison-Knudsen, Inc., to evaluate the use of roadheaders in underground mining operations. Road-headers were found to be widely used in mines as construction support units, as development miners, and as stoping machines. However, road-headers were found to have mechanical and electrical problems, to suffer reduced productivity when integrated into the mining cycle, and to create dust problems. Also high capital costs and low utilization and avail-ability cause high amortization costs per ton. This report identifies the roadheader operating problems and offers suggestions for improved mechanical and electrical design as well as manufacturer and owner responsibilities for improved availability. The development of a complex integrated excavation and ground support sys tern is no t warranted until the roadheader itself is made much more reliable.

Jan 1, 1980

By F. X. McCawley

The Bureau of Mines, in pursuing its goal of extending the life span of strategic materials, conducted field corrosion studies at the East Mesa Known Geothermal Resources Area (KGRA) in the Imperial Valley, Calif., to determine the optimum materials of construction for use in geothermal mineral energy resource recovery plants. These studies included characterization of geothermal environments and in situ corrosion testing. The corrosion resistance of 10 alloys exposed to 5 brine and steam process environments was evaluated using the low-salinity, high-temperature brine from geothermal well Mesa 6-1. Of these alloys, Hastelloy C-276, Hastelloy S, Incone1 625, titanium-2nickel, and 316 L stainless steel had excellent resistance to corrosion in all of the process environments; E-Brite 26-1 and 430 stainless steel had fair resistance. Although general corrosion rates for 4130 steel and 1020 carbon steel were substantially higher than those of the other iron-base alloys, these two alloys could prove useful in low-salinity process environments because of their low cost. Aluminum alloy 5005 was the least corrosion resistant alloy and pitted severely. Scales formed on all of the alloys in every process environment. Calcite, aragonite, and an amorphous silicate were the major components of the scales.

Jan 1, 1980

By Staff

This U.S. Bureau of Mines publication presents the results of investigations into the fire and explosion hazards of oil shale rocks and dust. Three areas have been examined: the explosibility and ignitability of oil shale dust clouds, the fire hazards of oil shale dust layers on hot surfaces, and the ignitability and extinguishment of oil shale rubble piles.

Jan 1, 1989

By T. E. Howard

The western phosphate field, comprising parts of Idaho, Montana, Wyoming, and Utah, contains one of the world's largest known reserves of phosphate rock. Although phosphate-rock deposits of good-grade have been known since before the turn of the century and production has been recorded since 1906, real development of this important field did not begin until immediately after World War II. Since then fertilizer-manufacturing facilities using western phosphate rock have been expanded, and three electric-furnace plants for producing elemental phosphorus have been installed, resulting in a rise in mine production from 323,955 long tons2/ in 1945 to 1,653,916 long tons3/ in 1953. Interest in the field is increasing, and it is reasonable to expect that the western phosphate industry will continue to expand. Before 1945 all western production was from underground mines. In that year the first strip mine in the field was started near Montpelier, Idaho,~ and in sub-sequent years a number of other open-pit mines were opened in southeast Idaho and western Wyoming. At present the major part of the production comes from surface mines. Underground mining has continued, and new underground mines have been opened in the field, but recent exploration by operating companies has been aimed primarily at developing additional deposits suitable for low-cost surface mining. Preliminary reserve estimates by the Federal Geological Survey5/ indicate that only a very small part of the total resource may be recovered by surface methods and that the industry eventually must depend largely on underground mining. Because one function of the Bureau of Mines is promoting the conservation and development of the Nation's mineral resources, it is appropriate that research be conducted to develop low-cost maximum-recovery underground mining methods applicable to western phosphate-rock deposits.

Jan 1, 1956

By M. H. Marvin

This report presents the results of a program to develop backfilling techniques to mitigate undesirable effects of hydraulic borehole uranium mining. Large underground cavities, formed during the borehole mining process, can be backfilled to prevent ground subsidence and to allow mining of adjacent uraniferous sandstone. Three backfilling techniques were tested in the laboratory and in the field: bulk dumping of slurry into the borehole from ground level, slurry injection under water, and slurry injection above the cavity water level. These techniques were tested with sand and with sand and one percent cement (by weight) mixtures. The project was accomplished in four tasks: equipment preparation and transport, mining operation to generate a full-sized cavity, backfilling operation, and assessment through core samples and subsidence checks. The concentrations of cement mixed with sand proved to be inadequate to bond the sand. Bulk dumping resulted in a 30-degree angle-of-repose, much too steep to completely fill the cavity. Both slurry injection techniques filled the cavity satisfactorily. However, underwater injection is the recommended backfilling technique because the borehole water level does not need to be pumped down during backfilling. The borehole itself was filled by bulk dumping of slurry. In conclusion, backfilling of borehole mining cavities is entirely feasible, and the preferred method is slurry injection under water.

Jan 1, 1979

By Vladimir Adamek

This paper describes the Bureau of Mines development of a novel subsidence prediction methodology suitable to the mining and geologic conditions in the Northern Appalachian Coal Region. It describes the computation of vertical and horizontal movements, inclination, curvature, and horizontal strains. The substance of this method is the separation of the effects of lithology by introducing a correlation between hypothetically homogeneous overburden and existing lithologic conditions, while providing for different mining conditions, i.e., underground geometry and overburden thickness. The effects of lithology have been expressed in the form of a variable subsidence coefficient within the subsidence trough. The subsidence co-efficient is considered a constant for other predictive methods. Field data from 16 test sites at 11 Bureau longwall panel studies were used in the analysis. For each panel, the characteristics of the variability of the subsidence coefficient were defined. Regression analysis of the subsidence coefficients from all test sites on their locations relative to the edges of their respective panels yielded a third-degree polynomial equation. The results from additional longwall panel studies, not included in the regression analysis, were used to prove the validity of this method. To facilitate the use of this precalculatlon methodology, a computer program was written in BASIC for use on a personal computer.

Jan 1, 1987

By D. R. Mathews

Electrorefined vanadium was evaluated with respect to tensile properties and the effects of interstitial contaminants in the temperature range of 77° to 273° K. The yield strength of 18,500 psi and hardness of 63 diamond pyra-mid hardness (DPH) of electrorefined vanadium are approximately equal to that of iodide crystal bar vanadium. The ductile-brittle transition temperature was found to be below 77° K, but with 0.175 weight-percent oxygen or 0.10 weight-percent nitrogen, it increased to between 123° and 190° K. With carbon content up to 0.11 weight-percent, the transition temperature remained below 77° K. The yield strength of the interstitial-containing alloys can be expressed by: au = 7.5 + 480 (pct N) + 290 (pct 0) + 280 (pct C), where au is the upper yield stress in 1,000 psi at 273° K. Profuse deformation twinning occurred in the alloys tested at 77° K. However, twinning could be suppressed by dissolved oxygen or nitrogen in excess of 0.15 and 0.086 weight-percent, respectively. Carbon, even though present in excess of the solubility limit, did not affect twinning.

Jan 1, 1965

By Christopher C. Jobes, Alan G. Mayton

The National Institute for Occupational Safety and Health (NIOSH) researchers have investigated seat design issues for the occupants and operators of underground mine transport vehicles relative to whole-body vibration (WBV) and mechanical shock. Considering the ergonomic and engineering improvements made to underground mine shuttle car seats, this study has focused on reducing injury risk by improving seating on transport vehicles such as scoops, mantrips, personnel carriers, and rail-mounted locomotives. Similarly, proposed seat design improvements included layering of various types of viscoelastic foam padding to isolate vehicle occupants and operators from adverse health effects of jarring/jolting exposure. This paper discusses the results obtained from laboratory vibration testing of new seat padding materials in seven configurations at the NIOSH – Pittsburgh Research Laboratory (PRL) showing that careful use of configuration and materials can reduce the operator’s exposure to WBV. In addition, results for four mine transport vehicles are presented from field data collection efforts at a Southwestern Pennsylvania mine showing that a NIOSH based design does reduce the operator’s exposure to WBV. Finally, the authors discuss efforts to develop and field test seat padding interventions using new padding materials and configurations based on the laboratory test results [The findings and conclusions in this report are those of the author(s) and do not represent the views of the National Institute for Occupational Safety and Health.]

By W. R. Crane

Subsidence and ground movement are phenomena common to and attendant upon practically all large-scale mining operations, and under certain conditions may occur in all workings, large and small. The interpretation of the cause of failure in rock masses involves a study of the nature of plants of weakness common to all rocks. The dominating planes of weakness can readily be determined by observation in any given locality, and in order of importance in the study of subsidence are (1) faulting planes, (2) bedding planes, (3) joint planes, and (4) other prominent planes of weakness such as thrust and shear planes and contacts. This report has mainly to do with the third item, joint planes, and is a preliminary statement which t to be followed by a more complete report in bulletin form.

Jan 1, 1931

By D. R. Wilburn

The Bureau of Mines investigated the potential availability of magnesium from 45 properties in market economy countries (MEC's). The 38 significant deposits evaluated have demonstrated resources of approximately 29 billion short tons (st) magnesium-bearing material containing 416 million short tons (MMst) magnesium oxide (MgO). Using data it gathered, the Bureau determined the magnesium production potential for each property including a 15-pct rate of return on invested capital. Total and annual availability assessments for the next 30 yr were completed for magnesium (Mg) metal, deadburned MgO, and caustic calcined MgO. At a January 1984 market price of $1.34/Ib Mg metal, the properties evaluated could economically produce an estimated 13 MMst Mg metal. At a market price of $400/st nonmetal magnesium product, these properties could economically produce 109 MMst deadburned MgO and 43 MMst caustic MgO. These properties could produce approximately 301,000 st Mg metal, 3.0 MMst deadburned MgO, and 430,000 st caustic MgO annually at current full production levels and 1984 market prices until at least the year 2000. Total 1984 MEC production assessed in this study was 153,000 st Mg metal and 4.3 MMst nonmetallic MgO products.

Jan 1, 1986

By W. W. Adams

"The results of the fourth annual safety contest, 'mown as the National Safety Competition, contacted by the United States Bureau of Mines are herein announced. A bronze trophy, ‘Sentinels of Safety’, the gift of the Explosives Engineer magazine, has been awarded to the leading mine in each of the five groups into which the mines and quarries that participated in the contest were arranged. These five groups were: anthracite mines, bituminous coal mines, metal mines, nonmetallic-mineral mines, and carries and open-pit mines. The leading plant in each group was the mine whose employee lost the smallest number of days from accidents in proportion to the total number of man hours worked. Where two or more mines operated without a lost-time accident, the winner was adjudged to be the plant which operated the largest number of man hours during the year.The contest was based upon reports of accidents and exposure sent by the competing companies to the Bureau of Mines. Records of the five leading companies in each group were made known to a Committee of Award, consisting of the following seven members: H. Poster Bain, Secretary of the American Institute of Mining and Metallurgical Engineers; James F. Callbreath, Secretary of the American Mining Congress; W. H. Cameron, Managing Director of the National Safety Council; H. L. Gandy, Secretary of the National Coal Association; A. T. Goldbeck, Director of the Engineering Bureau of the National Crushed Stone Association; William Green, President of the American Federation of Labor; and A. J. R. Curtis, Assistant to the General Manager of the Portland Cement Association. Members of the committee voted for the winning company in each group in accordance with the rules governing the contest.. A majority vote prevailed."

May 1, 1929

By Oren C. Baptist

Umiat field contains the largest accumulation of oil discovered so far in Naval Petroleum Reserve No. 4 in Arctic Alaska. The Umiat anticline was tested with 11 wells; 6 produced oil in varying quantities. Behavior of the wells during testing was unpredictable. For example, one well was abandoned as a dry hole after all tests failed to recover any oil, yet an offset well, only 200 feet from the dry hole, produced 400 barrels of oil a day. The main oil reservoirs are less than 1,000 feet deep and are in the permanently frozen zone (permafrost). Reservoir pressures are low, and most primary production will be by expansion of gas-in-solution in the oil. Because of the unusual reservoir conditions and the difficulties encountered in drilling and completing the wells, the Department of the Navy asked the Federal Bureau of Mines to make laboratory studies of the reservoir sand to determine the cause of well plugging and to provide laboratory information, to be used as an aid in estimating oil recovery from frozen reservoir rocks under solution-gas expansion from low-saturation pressure conditions.

Jan 1, 1960

By D. D. Hamilton

The ISMS program provided for the development and demonstration of equipment modifications for improved safety in both conventional and continuous coal mining systems. This report documents the success of the program in identifying accident hazards in underground coal mines with 4-to 8-foot seam heights, in designing modifications to reduce the hazards, and in demonstrating improved safety through extended underground use of the ISMS equipment.

Jan 1, 1977

By C. A. Herbert

In summer, when hot, moisture-laden air enters a coal mine in the region east of the Mississippi River, the moisture is likely to condense on the roof and ribs because the incoming air is cooled below its dew point upon contact with the roof, ribs, and floor of the mine passageways. When the roof and ribs become wet owing to this condensation they are said to "sweat." In many mines, as soon as this sweating begins, shale or slate roof that appears solid and strong in winter begins to cut and fall. For a long time most mining men believed (many still believe) that the roof trouble was due to this sweating. However, from observation of conditions in one mine the operators concluded that the trouble was caused by expansion and contraction of the roof due to changes of temperature. This opinion was confirmed by experiments at several mines in cooling the air as it entered the mines. Methods used in these mines for cooling the air are described in this circular. MINE A At mine A the roof gave considerable trouble in the summer, and it was observed that where a spray of water from a leaking dam kept the roof wet and at a uniform temperature no difficulty was experienced with the roof, although it had cut and fallen on either side of that point. From this fact the company officials concluded that changes of temperature in the air rather than moisture caused the trouble and that if the incoming air were cooled to approximately normal strata temperature much of the additional roof trouble experienced during the summer would be overcome.

Jan 1, 1940

By Milford L. Skow

This report summarizes the principal activities and results of 15 years of research by the Bureau of Mines, U.S. Department of the Interior, on methane control in coal mines. This research has investigated fundamental factors regarding the occurrence and movement of methane in coal beds, removal of methane prior to mining, and control of methane during mining. The report includes a bibliography listing the more than 150 publications resulting from the Bureau's methane control program as well as numerous other references, a section on methane recovery and use, a look at the upcoming Bureau of Mines research program, and a brief review of methane drainage practices in other coal-producing countries.

Jan 1, 1980

By D. Harrington, W. J. Fene

For nearly 30 years the Bureau of Mines has contended that mine explosions can be prevented and has pointed out to the industry ways and means by which they could be avoided. The record of co2l-mine explosions • during the past fiscal ?Bar bears out the :Bureau1s contention, inasmuch as fewer men were killed by coal-mi~e e:xplosions in the United States during that year than in :gi_y corresponding 12 months in the history of coal mining in the United States, insofar as records are available; and more than a year has elapsed since·a major explosion (in which five or more men were killed) has occurred, this being t.1-J.e first continuous 12- month period without a major coal-mine explosion disaster in the United States in more than 60 years. The methods of preventing mine e:iiplosions are well known to experienced, well-informed persons cngnged in coal mining. Despite this knowledge, many coal-mine operutors continue to use practices and methods that they should know have resulted in countless explosions, and mine workers persist in following past procedure or in breaking safety rules and practices almost certain eventually to result in disaster. ' Virtually all explosions are the result of human failure, such as carelessness or neglect by officials or workers or others. These human failures can be corrected chiefly by ed.ucation and proper and adequate supervision and strict discipline. In some instances mine officials are ·lax, careless, poorl~• informed, and often incompetent; end in many instances miners have repulsed the introduction of known preventive methods because of sheer obstinacy, ignorance, heedlessness, or possibly fear that the operator was trying to o'bta.in some unfair adva.,.'1. tago or would neglect some other phase of accident or e,:plosion prevention. The freedom of the fiscal year 1938-39 from major coal-mine explosions ar..d frora any considera~le number of fat,JJ.i ties from minor explosions is a. matter for congratulation, but on the other hand. the occurrence of one rather bad e~losion in each of tho 3 calendar years 1937

Nov 1, 1939

By William Seymour

"INTRODUCTION Byproduct-coke manufacture is one of our country's most essential in¬dustries; its importance was strikingly accentuated by the demands of World War II. This paper reviews recent progress in various phases of byproduct-coke operations for the production of metallurgical coke particularly that used as blast-furnace fuel.In the early days of the by-product-coke industry in the United States high-grade bituminous coking coals, both high-volatile or gas coal and low-volatile Pocahontas coal, were plentiful, and the selection and mixing of coals for coke-oven use were minor problems.The demands of World War I for the production of iron, steel, and coke aroused and stimulated new interest in the investigation of the reserves, characteristics, and properties of our coking coals. During that war the increased demand for coke reached a critical stage, and the shortage of high-grade coking coals necessitated the use of cols of inferior quality and of different coking characteristics than those previously used.The period of prosperity following World War I brought much progress and development in the by-product-coke industry. Methods of testing coal and coke were improved. The search for satisfactory coking coals was continued, and construction and design of byproduct ovens were improved."

Jun 1, 1946

The Mateen deposit comprises two large spodumene-bearing pegmatite dikes that outcrop along the, side and crest of a hill overlooking 'Rill City in the southern Black Hills of South Dakota. The Bureau of Mines investigated the Mateen deposit as part of a comprehensive study of the lithium mineral-production possibilities in the Black Hills area. The work was undertaken during the second World War, when the demand for certain lithium salts and compounds exceeded the small productive capacity of the industry. During the course of the investigation, the Bureau of Mines took 61 large channel samples from surface trenches, 4 channel samples from a shaft, and 3 from the face of an open cut. In addition, 8 diamond core-drill holes were completed to investigate the attitude of one of the dikes at depth. Metallurgical tests were conducted by the Bureau of Mines to determine the feasibility of beneficiating spodumene-bearing ores from the Mateen dikes.

Jan 1, 1948

By M. P. Dalton

This paper which describes the milling practice at the Morning concentrator of the Federal Mining and Smelting Co., Mullan, Idaho, is one of a series being prepared by the Bureau of Mines. ACKNOWLEDGMENT The author wishes to acknowledge the assistance given by H. G. Washburn, general manager of the Federal Mining and Smelting Co., and by C. S. Price, assistant mill superintendent, in the preparation of this paper.

Jan 1, 1932

By E. Owens, R. Gudavalli, D. Wilder, T. Xia

As mechanical shock and vibration environments evolve, it is important to understand their potential effect on human operators. Human beings are sophisticated mechanisms comprised not only of passive components with mass, damping, and stiffness characteristics, but also of components that can actively affect apparent mass, stiffness, and damping. Because the lumbar spine can exhibit local, short-column buckling, stability of the human trunk depends on the responsiveness of the neuromuscular control system.1-2 We have been evaluating the ability of patients with back pain to respond to a series of sudden loads. We believe the results have implications for isolation design and standards development. Methods 153 patients, aged 21 to 55, presenting with back pain agreed to enroll in a research study that randomly assigned them to one of three treatment arms: high velocity low amplitude spinal manipulation, low velocity variable amplitude spinal manipulation, or wait for 2 weeks and then be randomized to one of the above groups. Response to sudden load testing was one of a battery of baseline evaluations performed upon entry into the study and prior to treatment. EMG electrodes were attached to the skin over the paraspinal muscles of the standing participant bilaterally 3 cm from midline at the L3 level. While standing upright on a force plate (Bertec), participants were fitted with a strap around their back and hooked to a load cell in front of their chest. An accelerometer was rigidly attached to the load cell. Impact was applied to the chest using a cord attached to a falling weight. The weight’s fall distance was varied between 9 and 13 inches to account for the size of the subject. The subject was blindfolded and wore headphones playing white noise to prevent cueing of when the weight was dropped to apply the load. Hence, although the participant knew a load was about to be applied, he or she did not know the instant it would occur. Just before the weight was dropped, a 4 second data collection process was started for the two EMG electrodes, load cell, accelerometer, and force plate. The load drop was repeated 6 times, at irregular intervals, over a period of 2 minutes. The raw data thus collected was reduced to obtain several values: 1) length of time from the pull on the harness to the beginning of the response of the left and right paraspinal muscles (LES, RES), 2) time and magnitude of the maximum response, 3) force and acceleration experienced at the chest, and 4) the time and magnitude of the center of pressure location (COP). A general linear model was used to evaluate the results. Results For the EMG data, of the 1,824 observations made, 90% of them indicated a response. Prior to the sudden load, resting muscle activity was different between left and right sides (p=0.0001) and between males and females (p=0.0001). Female subjects began to respond to the sudden load within 92 to 110 ms and males from 101 to 109 ms. Females exhibited more variation in starting

Jan 6, 2006